Rail flaw detector mechanism



June 22, 1943. G. L. JONES 2,322,452 RAIL FLAW DETECTOR MECHANISM .FiledAug. 19, 1941 FIG.2.

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"V V Y V y I I I r INVENTOR u era/re: 15572:? la/V58 BY 1 g/ PatentedJune 22, 1943 UNITED STATES PATENT I OFFICE RAIL FLAW DETECTOR.MECHANISM George Lester Jones, Garden City, N. Y,, assignor to SperryProducts, Inc., Hoboken, N. J., a corporation 01' New York ApplicationAugust 19, 1941, Serial No. 407,391

9 Claims.

This invention relates to rail flaw detector mechanisms and isparticularly designed for application upon the type of detectormechanism employed on the Sperry rail fiaw detector car. This caroperates upon the principle of passing current through the rail toestablish an electromagnetic field surrounding the same and exploringsaid field by inductive means to discover any irregularities caused bythe presence of fissures or other discontinuities in the rail. Theparticular problem which presents itself here arises from the fact thatrails are joined by angle-bars, bolts, etc., which joints constitute inthemselves irregularities in the rail which will cause variations in theelectromagnetic field in the same manner as an internal fissure.Therefore, for the interval during which the inductive detector means ispassing over the rail joint the Sperry car employs a mechanism forshort-circuiting the connection between the detector mechanism and theindicating mechanism so that the irregularities caused by the rail jointwill have no effect upon the indicating mechanism.

The specific joint cutout mechanism to which this invention relatesconsisted of a pivoted finger carried by the detector carriage inadvance of the detector mechanism and adapted to engage the angle-bar atthe joint before the detector mechanism reached the angle bar.Throughout the timethat the joint finger rode along the angle-barthejoint cutout mechanism was effective and when the joint finger left theangle-bar the detector mechanism would ordinarily again becomeeffective. This was not desirable because, since the joint cutout fingerwas positioned in advance of the detector mechanism, the detectormechanism would still be over the angle-bar when the joint finger hadleft the bar. Therefore it was proposed to provide a delayed actionarrangement in the short-circuiting mechanism controlled by the jointfinger, so that the short-circuit would'remain effective for apredetermined interval after the joint finger had left the angle-bar andsuflicient to permit the detector mechanism also to pass beyond theangle-bar,

The above described arrangement would be satisfactory if the detectorcar always proceeded at substantially the same rate, or within a verynarrow range. In recent years, however, detector cars have been operatedat higher speeds normally, but when passing through frogs, switches,etc. it was necessary to slow down the car appreciably. Thus, whereas acar might test at a normal testing speed of 9 or 10 miles an hour,

this speed would be cut down to 5 or 6 miles an hour when testingthrough frogs and switches. It will now be seen that if a time delaywere introduced in the short-circuit between the detector mechanism andthe indicator mechanism sufficient just to permit the detector mechanismto pass beyond the angle-bar when the car was travelling 10 miles anhour, this delay would be insuffi'cient when the car was travelling 5miles an hour, in which case an appreciably longer time delay would benecessary to permit the detector mechanism to pass beyondthe angle-bar.If the additional delay were not provided when the car operated at aslower speed, then the short-circuit between the detector mechanism andthe indicating mechanism would be rendered inefi'ective while thedetector mechanism was still above the angle-bar, and as a result theelectromagnetic field distortion caused by the anglebar would operatethe indicating mechanism in the same manner as a fiaw.. This condition,therefore, resulted in false indications which required an operator tostop the car for investigation of the rail or else for readjustment ofthe cutout system.

It" is the principal objec of this invention to provide means whereby te time interval which elapses between the tim that the joint fingerleaves the angle-bar a the time that the detector mechanism is againeffective to operate the indicating mechanim may be varied either atthewill of the operator by manual setting when the operator slows down thedetector car. and in proportion to said slowing down, or whereby saidtime delay interval may be automatically varied in response to thevarying speeds'of the detector car.

Further objects and advantages of this invention will become apparent inthe following deta led description thereof.

In the accompanying drawing,

Fig. 1 is a side elevation of a portion of the ra l fissure detector carhaving my invention applied thereto.

Fig. 2 is a side elevation of a portion of the truck of a rail fissuredetector car showing the driving mechanism employed in this invention.

Fig. 3 is a wiring diagram.

Fig. 4 is a portion of a wiring diagram showing a modified hand operatedform.

Referring to Fig. 1 of the drawing, there are shown the parts of astandard Sperry rail fissure detector car which includes a car body [0013- era-ting along the rails R. Fissure detection is accomplished bypassing current through each rail from a generator within the car bodysupplying current to spaced curre'nt brushes II and l2 supported uponthe current brush .carrlage l3 which when in lowered or effectiveposition is adapted to ride upon the rail by means such as wheels IS.The current brush carriage I3 is normally held in elevated orineffective position by means of springs, not shown, and cables l6, butwhen it is desired to lower said carriage, fluid pressure'such ascompressed air is supplied to the cylinders I! to force out pistons l8Which are pivotally connected at 19 to the current brush carriage l3.The current passed through the rail by Way of spaced brushes H and'l2will establish an electromagnetic field surrounding the rail and thisfield will be uniform except in the region of flaw, where it will bedistorted. Such distortions of the electromagnetic field are detected bya flaw responsive mechanism 20 which may take the form of a pair ofopposedinduction coils 22 supported in a housing 23 at a constantdistance above the rail surface by means of a carriage 24. Saidfcarriage 24 is mounted on current brush carriage l3 by means of looselyfitting bolts 25 and springs 26 to permit said carriage 24 while ridingon the rail 0n means such as wheel 21, to move independently of carriagel3 so that the said carriage 24 may at 'all times maintain parallelismwith the rail surface regardless of lrregularities thereof. The coils 22normally cut the same number of lines of force, but on entering a regionof flaw, first one coil and then the other will cut a different numberof lines of force to generate a differential E. M. F. which after beingsuitably amplified by an amplifier A may be caused to actuate a pen Poperating on a chart C. At the same time that'the pen is actuated, thereis actuated also marking means which may take the form of a paint gun 30mounted on the current brush carriage l3 a sufiicient distance behindthe flaw responsive members 22 to compensate for the movement of the carand for the lag in operation of the paint gun.

As stated in the introduction hereto, the rails are held together byjoints which may comprise.

an angle-bar .32, bolts 33, and additional members, all of whichconstitute the rail joint, and this rail joint serves to deflect thecurrent passing through the rails and vary the .electromag-. netic fieldsurrounding\the same- Unless means were provided for preventing suchaction, it is understood that the searching unit would respond to thevariation/ in electromagnetic field caused by the railjoint just thesame as it responds to variations in the said field caused by fissuresand other defects. Since it is not desired that the indicating mechanismand the paint gun be operated at 'every joint, means are provided forcutting out the action of the indicating means for the interval duringwhich the searching unit is passing through the region of theelectromagnetic field which is affected by the rail joint. The mechanismheretofore employed and to which this invention relates consists of a.joint finger 40 pivoted at 4! on the current brush carriage and sopositioned as, to slide along the edge of the rail so that it willengage the angle-bar which will tilt the finger about its pivot. Suchtilting is caused to close a set of contacts 42 (see Fig. 3) to close acircuit comprising a battery B and a relay 43 comprising a coil-'44 andarmature 45, which coil attracts its armature to close a short-circuitbetween the search unit 20 and the amplifier A. When the coil 44attracts its armature. sets of contacts 46, 41 are closed, and the eunit by way of points a, b, 46, 41, c, d, and a, b,"

' bar.

is established a circuit extending from the search bar the shortcircuits described above will be effective to prevent the search unitfrom send ingsufficient impulses into the amplifier to operate theindicating mechanism. When the finger 40 leaves the angle-bar, thiswould ordinarily open contacts 42 and again permit the search unit 20 tosend impulses into the amplifier A. When finger 40 has left theangle-bar, it will be seen that the search unit is still over said barand in the field of distortion caused by the bar. This would result inan impulse being transmit-, ted by the search unit to the amplifier andwould cause operation of the indicating means to give a falseindication. The indication is false because it does not indicate theregion of a defect but is due entirely to the rail joint. It isdesirable, therefore, that a. time delay be introduced in the shortcircuits between the searching unit and the amplifier so that saidcircuits will not open for a predetermined interval after contacts 42have opened. For this purpose the coil 44 has a parallel circuitextending from the coil to points g, h, resistance R, R and return tothe relay coil. It will now be seen that here is a closed parallelcircuit through which the current of battery B is' normally flowin whilecontacts.

42 are closed, but when contacts 42 are opened there is generated in thesaid closed parallel circuit, by reason of its self-inductance, avoltage which will cause current to flow in the said closed circuituntil the current thus induced is dissipated. The rate of dissipation ofsaid induced current will depend upon the amount of resistance in theclosed circuit. The greater the resistance the quicker the inducedcurrent will be dissipated.

Heretofore, an amount of resistance was placed in the said parallelcircuit calculated for a given speed of car, so that at the said carspeed, when the finger 40 had left the angle-bar, a sufiicient intervalwould elapse so that the searching unit 20 would just pass the'leavingend of ,the angle- Thls condition was satisfactory while detector carsoperatedat relatively low speeds of between 5 /2 and 6 /2 .miles perhour. However, when the cars began to operate at higher speeds up to thepresent rate of. 10 miles per hour, this condition of pre-setting of theresistance in the time delay circuit was unsatisfactory because therewere times when thecar had to be operated at slower speeds as low as5.miles per hour for given conditions of track. The variation between 10miles per hour and 5 miles per hour is so steep that a time'delaycircuit set for the higher speed will result in the circuits between thesearch unit and the amplifier becoming effective while the search unitis still over the angle-bar if the car is travelling at the lower speedof 5 or 6 miles per hour. To obviate this condition and to permit thecar to operate with freedom from false indications due to jointsregardlessof the v speed of the car, I have provided means wherebyeither automatically in response to the speed of the car, or at the willof the operator without leaving the car, the said time delay circuit mayv aaaaaa be varied in a manner to accomplish the desired result.

In Fig. 3 I have disclosed a form of invention wherein the time delayfollowing the opening of circuit N, g, h, R, R, 44, a constructionwhereby more or less resistance may be introduced in or cut out of thesaid circuit, depending upon the speed of the car. For this purpose theresistance R comprises a plurality of resistance elements r, 'n, n. Whenthe car is travelling at low speed, for instance 5 to 6 miles per hour,the said resistance elements 1'; r1, r: are short circuited by a shuntleading from h to switch S, switch S, switch 8'', to. 1. Thus none ofresistance R is in the circuit and the closed parallel circuit offers aminimum of resistance to the current induced when contacts 62 areopened. Therefore it will take the maximum time within which todissipate the said induced current. This is the condition which isdesired because at the slow rateof speed of the car a longer intervalelapses between the time that joint finger Mi passes off the anglebarand the time that the search unit passes off the angle-bar. As the speedof the car increases, switch S is designed to open and the closedcircuit now extends through point h, resistance 12, point k, switch S,switch S" to point 7. Thus resistance rz has been introduced in theclosed circuit and the induced current will be dissipated somewhat morerapidly than when switch S was also closed. Similarly, as the car speedsup, switches S and S are designed to open so that the closed circuitwill lie through h, m, n, n. switch S", point 1. Thus resistances 11 and1-2 are now in the closed circuit and the induced current will bedissipated still more quickly. Finally, when the car reaches 9 miles perhour, all three switches S, S, S" are designed to open, and the closedcircuit now lies through h, resistance 12, resistance r1, resistance r,to point 7. Thus all of resistance R is now in the circuit and theinducedcurrent will be dissipated rapidly.

For controlling the switches S, S, and S" in response to the speeds ofthe car, there are provided coils C, C, C" connected in series with eachother and with a magneto M. This magneto may be mounted on the truck Tshown in Fig. 2 and designed to be driven from an axle pulley 68 on thetruck axle Bl by means of cable $2. The magneto will thus generate acurrent which is a function of the speed of the car. The coils C, C, C"are of such properties that at slow speed of the car, magneto M isgenerating only enough current to permit coil C to attract its armatureand open switch S. As the speed increases, magneto M generates enoughcurrent so that coils C and C can attract-their armatures and thus openswitches S and S; while, at the speed of 9 miles per hour or more, 'themagneto is delivering enough current to energize all three coils so thatI all three switches can be opened.

Ina modified form of the invention as disclosed in Fig. 4 the operatormay control the resistances 1', r1, 12 by operating the, switches S, SS" by hand. Thus, when the car is operating at its normal, relativelyhigh testing speed, the operator will open all three switches so thatthe maize imurn resistance is present in the closed circuit. When hefinds it necessary to slow down the car he will close one or more of theswitches, depending upon the amount of reduction in speed of the car, soas to short out one or more of the resistance elements 2, 1'1, 1' toincrease the time delay of the closed circuit corresponding to theamount of decrease in the speed of the car.

In accordance with the provisions of the patent statutes, I have hereindescribed the principle and operation of my invention, together withtheapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by otherequivalent means. Also, while it is designed to use the various featuresand elements in the combination and relations described, some of thesemay be altered and others omitted without interfering with the moregeneral results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent is:

1. In a rail fiaw detector car adapted to travel over rails connected byjoints, means for establishing an electromagnetic field surrounding therail, means responsive .to variations in said field caused by defects inthe rail, said means respond ing also to variations in said field causedby said joints, cutout means carried by said detector mechanism inadvance of said responsive means and adapted to cooperate with saidjoints, means for short-circui-ting the output of said responsive means,means whereby said short-circuiting means is rendered eflective whensaid cutout means is in cooperative relation to said joints, means formaintaining said short-circuiting means effective for a predeterminedlength of time after said cutout means has passed out of cooperativerelation tosaid joint, and means responsive to the speed of the caralong the rails for varying the predetermined length of time in inverseratio to the speed.

2. In a rail fiaw detector car adapted to travel over rails connected byjoints, means for establishing an electromagnetic field surrounding therail, means responsive to variations in said field caused by defects inthe rail, said means responding also to variations in said field causedby said joints, cutout means carried by said detector mechanism inadvance of said responsive means and adapted to cooperate with saidjoints,

3. In a rail flaw detector car adapted to travel over rails connected byjoints, means for establishing an electromagnetic field surrounding therail, means responsive to variations in said field caused by defects inthe rail, said means responding also to variations in said field causedby said joints, indicating means, means. whereby said responsive meansactuates said indicating means, cutout means carried by said detectormechanism in advance of said responsive means and adapted to cooperatewith said joints, means whereby said cutout means renders saidresponsive means ineffective to actuate said indicating means when saidcutout means is in cooperative relation to said joints, means formaintaining said responsive means ineffective to actuate said indicatingmeans for a predetermined length of time after said cutout means haspassed out of cooperative relation'to said joint, and means responsiveto cutout means carried by said detector mechanism in advance of saidresponsive means and adapted to cooperate with said joints, meanswhereby said time after said cutout. means has passed out of cooperativerelation to said joint, said last named means comprising a closedcircuit having induct-- length of time, said last-named meanscompriscutout means renders said responsive means ineffective to actuatesaid indicating means when said cutout means is in cooperative relationto said joints, means for maintaining said responsive means ineffectiveto actuate said indicating means for a predetermined length of timeafter said cutout means has passed out of cooperative relation to saidjoint, means for varying said predetermined length of time, and meanswhereby said last-named means is controlled in accordance with the speedof said car along the rails.

5. In a rail fiaw detector car adapted to travel over rails connected byjoints, means for establishing an electromagnetic field surrounding therail, means responsive to variations in said field caused by defects inthe rail, said means responding also to variations in said field causedbysaid joints, cutout means carried by said detector mechanism inadvance of said responsive means and adapted to cooperate with saidjoints, means for short-circuiting the output of said responsive means,means whereby said short-circuit means is rendered efiective when saidcutout means is in cooperative relation to said joints, means formaintaining said short-circuiting means effective for a predeterminedlength of time after said cutout means has passed out of cooperativerelation to said joint, said last named means comprising a closedcircuit having inductance and resistance therein, means whereby acurrent is induced therein when said cutout means passes out ofcooperative relation to said joint, and

means for varying said predetermined length of time, said last-namedmeans comprising means responsive to the speed of the car along therails for varying the resistance in said closed circuit in direct ratioto the speed.

. 6. In arail fiaw detector car adapted to travel over rails connectedby ,joints, means for establishing an' electromagnetic field surroundingthe rail, means responsive to variations in said field caused by defectsin the raiLsaid means responding also to variations in said field causedby said joints, cutout means carried by said detector mechanism inadvance of said responsive means and adapted to cooperate with saidjoints, means for short-circuiting the output of said responsive means,means whereby said short-circuiting means is rendered eifective whensaid cutout means is in cooperative relation to said joints, means formaintaining said short-circuiting means effective fora predeterminedlength of me means controlled by the speed of the car, and means wherebysaid speed-controlled means varies the resistance in said closedcircuit.

7. In a rail flaw detector car adapted to travel over rails connected byjoints, means for establishing an electromagnetic field surrounding therail, means responsive to variations in said field caused by defects inthe rail, said means responding also to variations in said field causedby said joints, cutout means carried by said detector mechanism inadvance of said responsive means and adapted to cooperate with saidjoints, means for short-circuiting the output of said responsive means,means whereby said short-circuiting means is rendered effective whensaid cutout means is in cooperative relation to said joints, means formaintaining said short-circuiting means effective for a predeterminedlength of time after said cutout means has passed out of cooperativerelation to said joint, said last named means comprising a closedcircuit having inductance and resistance therein, means whereby acurrent is induced therein when said cutout means passes out ofcooperative relation to said joint, and means for varying saidpredetermined length of time, said last-named means comprising meanscontrolled by the speed of the car, and means whereby saidspeed-controlled means varies the resistance in said closed circuit indirect ratio to the speed of said car along the rails.

8. In a rail flaw detector car adapted to travel over rails connectedby'join-ts, means for establishing an electromagnetic field surroundingthe rail, means responsive to variations in said field caused by defectsin the rail, said means responding also to variations in said fieldcaused by said joints, cutout means carried by said detector mechanismin advance of said responsive means and adapted to cooperate with saidjoints, means for short-circuiting the output of said responsive means,means whereby said short-circuiting means is rendered effective whensaid cutout means is in cooperative relation to said joints, means formaintaining saidshort circuiting means effective for a predeterminedlength of time after said cutout means has passed out of cooperativerelation to said joint, said last named means comprising a closedcircuit having inductance and resistance therein, means whereby acurrent is induced therein when said cutout means passes out ofcooperative relation to said joint, and means for varying saidpredetermined length of time, said last-named means comprising a magnetoadapted to be driven in accordance with the movements of the car, aplurality of relays of diiferent strengths connected in series with saidmagneto, and means whereby said relays control portions of saidresistance in said closed circuit caused by defects in the rail, saidmeans responding also to variations in said field caused by said joints,cutout means carried by said detector mechanism in advance of saidresponsive means and adapted to cooperate with said joints, cutoutoperating means for rendering the output of said responsive meansinefiective, means whereby said operating means is rendered effectivewhen said cutout means is in cooperative relation to a said joints,means for maintaining said operat ing means efiective for apredetermined length of time after said cutout meanshas passed out ofcooperative relation to said joint, means for varyme said predeterminedlength of time and means ,3 whereby said last-named means is controlledby the speed of said car along the rails.

GEORGE LESTER JONES.

